I remember a throwaway comment in one of the early 50s about it
Whoa. I knew Naruto had been going a long time, but it was last slated to finish in the early 50s? Six decades of filler seems like pushing it.
Think he meant Volume 50, not chapter 50 haha
Yup. Just taking a look through my volumes, it was in 47, so I was close:
The plot development toward the finale having been settled, I am drawing full steam ahead! Please continue enjoying Naruto until the end!!
He referenced it again in 48:
Ever since I wrote in the author's note of the previous book, volume 47, "The finale having been settled, I am drawing full steam ahead," lots of fans have been asking me, "Is the series ending soon?" but it is simply that the premise has been set; it will keep going for a long, long time! I shall not stop drawing at full stream, so please continue enjoying Naruto until the end!